1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor device, and in particular, it relates to a method of manufacturing a thin, flexible (having a flexible property) semiconductor device. Further, the present invention relates to a method of reducing parasitic capacitance which is generated between wirings formed on differing layers through insulating films. Note that the term semiconductor device in this specification indicates general devices which function by utilizing semiconductor properties, and that in particular, the present invention can be suitably applied to integrated circuits using elements having SOI (silicon on insulator) structures in which a semiconductor layer is formed on an insulator, to active matrix liquid crystal display devices structured using thin film transistors (TFTs), to active matrix EL display devices, and the like. The term thin film device indicates an electronic device containing a thin film transistor (TFT) structured using a semiconductor thin film, and at least one element from among elements such as wirings, conductive layers, resistors, and capacitive elements.
2. Description of the Related Art
Integrated circuits using elements having SOI structures in which semiconductor layers are formed on an insulator exist as one kind of semiconductor device. It is possible to have little parasitic capacitance, and to have high operation speed, by forming semiconductor layers on insulators.
One type of semiconductor device is an active matrix liquid crystal display device. Structures in which a substrate on which thin film transistors (TFTs) are formed and used as switching elements of pixels (TFT formation substrate), and a substrate on which an opposing electrode is formed (opposing substrate) are joined, and liquid crystals are injected in a gap between the substrates, is prevalent for active matrix liquid crystal display devices. The voltage applied to the liquid crystals can be controlled for each single pixel by the TFTs formed on a transparent substrate such as glass, and therefore active matrix liquid crystal display devices have clear images and are widely used in office automation equipment, televisions, and the like.
Further, active matrix EL display devices are known as one type of semiconductor device. Active matrix EL display devices have a structure in which an EL material is sandwiched between two electrodes, and an electric current flows, thereby causing light to be emitted. The electric current flowing in the EL material can be controlled for each single pixel by using a plurality of pixel transistors, and therefore an image is clear.
The level of integration for these types of semiconductor devices is increased and becoming minute. Parasitic capacitance which is generated between wirings of a semiconductor device leads to electric signal propagation delays, and this hinders high speed operation and accurate electric signal propagation. There are two types of parasitic capacitance, one which is generated between wirings formed on the same layer, and one which is generated between wirings formed on different layers through an insulation film.
If the level of integration is increased, the distance between wirings formed on the same layer becomes smaller, thereby increasing the parasitic capacitance. Wirings may be moved to different layers in order to reduce the parasitic capacitance between wirings formed on the same layer. Namely, the integration level of wirings on the same layer is spread among several layers. Lowering the parasitic capacitance which is generated between wirings formed on different layers, through an insulation film, contributes to an improvement in the overall integration level of the semiconductor device.
There are methods such as making insulation films thicker and increasing the distance between wirings, and using insulation films having a low dielectric constant, in order to reduce the parasitic capacitance generating between wirings formed on different layers through an insulation film. However, if the insulating film is made thicker, then not only does it become more difficult to form an opening portion in the insulation film in order to make a conductive connection between wirings, but there are also cases in which problems such as conductive layers formed by sputtering, for example, breaking in the inside of the opening portion, or being unable to ensure a sufficient film thickness, with the resistance therefore becoming large. Further, insulation films having low dielectric constants have a likelihood to develop problems relating to film quality, such as resistance to heat and permeability, and manufacturing problems such as dimensional changes due to etching. For example, although dependent upon the etching conditions, the hole diameter may become larger to approximately 1 xcexcm for a case in which a 1 xcexcm thick acrylic is used, and there may be damage in improving the overall level of integration of the semiconductor device.
In addition, there is a method in which the formation order of the conductive layers used for forming the wirings is changed. For a case structuring integrated circuits, having two layers of wirings for making the conductive connection between elements, by top gate transistors, the following order of formation is normally used: active layer; first insulation film (gate insulation film); first conductive layer (gate electrode); second insulation film (first interlayer insulating film); second conductive layer (first wiring); third insulation film (second interlayer insulating film); and third conductive layer (second wiring).
If the structure is changed to the following: first conductive layer (second wiring); first insulation film (lower portion insulation film); active layer; second insulation film (gate insulation film); second conductive layer (gate electrode); third insulation film (first interlayer insulating film); and third conductive layer (first wiring); then the distance between the first wiring and the second wiring becomes large, and the parasitic capacitance generating between the wirings can be reduced.
The distance between the first wiring and the second wiring becomes large in this case, and problems relating to openings and the conductive connection can be prevented through the active layer, for example. However, even with the same second wiring, with the latter case a material able to withstand the film formation temperature of the subsequently formed active layer and the thermal activation temperature of injected impurities must be used, and the same materials cannot always be used by the former and latter cases. For example, Al is often used as a wiring material having a low resistivity, but its resistance to heat is low, and it cannot be used in the latter case.
Note that, within this specification, an electrode is a portion of a wiring, and the terms wiring and electrode are used separately for convenience. However, the term wiring is always contained within the word electrode.
Semiconductor devices like those stated above are recently being used in portable devices and the like, and there are demands to make the portable devices thinner, lighter, and more flexible (flexible property). The major portion of the thickness of a semiconductor device is the thickness of its substrate, and the substrate may be made thinner in order to make the portable device thinner and lighter. However, if the substrate is made thinner, then manufacturing becomes difficult due to trouble in photolithography processes caused by warping of the substrate during manufacture, and substrate breakage more easily occurring during transportation of the substrate. A light, flexible display device can be manufactured, provided that a semiconductor device can be manufactured on a transparent plastic substrate or the like, but this has not yet been accomplished due to problems such as the heat resistance of plastic substrates.
Further, high speed operation of electric circuits and accurate propagation of electric signals can be performed for reducing the parasitic capacitance which is generated between wirings formed on different layers through an insulation film, thereby being able to use wiring materials having a low thermal resistance, such as A1, which have not been able to be used.
The inventors of the present invention considered a method of manufacturing a thin film device on a substrate possessing sufficient resistance to heat and strength during manufacturing, and then removing the substrate. First, a thin film device is formed on a first substrate, and then a second substrate is bonded. In this state, the thin film device exists between the first substrate and the second substrate. The first substrate is then removed, leaving the thin film device retained on the second substrate. An opening portion for reaching the thin film device retained on the second substrate is formed, and necessary processing such as forming a conductive layer so as to contact the thin film device through the opening portion, is performed, and the second substrate is also removed.
In addition, in the present invention, the first substrate and the second substrate are bonded by coating an adhesive in a portion of regions in which the thin film device is not formed. Alternatively, an adhesive is applied to a portion of the regions in which the thin film device is not formed, and other portions are temporarily restrained using a material such as viscous adhesive material. The second substrate can thus easily be removed by cutting the bonded portions.
The thin film device is always retained on one of the substrates if the above method of manufacture is used, but both substrates are peeled off in the end, so the first substrate and the second substrate may be thick, and substrates having sufficient strength can be used. In addition, little substrate warping and substrate breakage develops, resulting in that the manufacture is easy.
Flaws to the back surface of the substrate during substrate transportation in display devices such as active matrix liquid crystal display devices and active matrix EL display devices are a cause of a drop in display product quality, and this becomes a problem. The substrates used for support during manufacture are removed if the above method of manufacture is used, and therefore this problem is also resolved.
In addition, output electrodes can be formed in both the obverse and reverse sides of the thin film device if the above method of manufacture is used. If these are overlapped, then they can be applied to a three dimensional package and the like.
Further, there is also another invention in which a second wiring is formed in the side opposite to a first wiring with respect to an active layer, after forming: an active layer, a first insulation film (gate insulation film); a first conductive layer (gate electrode); a second insulation film (first interlayer insulating film); and a second conductive layer (first wiring), in order. Namely, a structure to be realized in which: a first conductive layer (second wiring); a first insulation film (lower portion insulation film); an active layer; a second insulation film (gate insulation film); a second conductive layer (gate electrode); a third insulation film (first interlayer insulating film); and a third conductive layer (first wiring) are formed. Note that, in this specification, the term active layer indicates a layer composed of a semiconductor film containing a channel region, a source region, and a drain region.
Parasitic capacitance generated between the first wiring and the second wiring can be reduced by the above structure, and the wirings are formed after forming the active layer. A material having a low resistance to heat can therefore be used.
Two substrates are used in the present invention in order to realize this type of structure. A thin film device is formed on the first substrate, and the second substrate is bonded to the surface on which the thin film device is formed. The first substrate is removed using a method such as mechanical grinding or chemical grinding, with the thin film device supported on the second substrate. The back surface of the thin film device is exposed when the first substrate is removed, and therefore wirings are formed. Wirings can therefore be formed on the top and bottom sides of the active layer. Cases in which transistors are formed on the first substrate, cases in which bottom gate transistors are formed, and cases in which top gate transistors are formed can be similarly structured. Note that the term bottom gate thin film transistor indicates a thin film transistor in which an active layer is formed in a layer between a gate electrode and a wiring, as shown in FIG. 27, in this specification.
Furthermore, by forming a top gate transistor on the first substrate, and then forming wirings only on the bottom side of the active layer, a transistor which becomes a bottom gate structure can be structured after removing the first substrate, provided that the manufacturing method of the present invention. In this case, parasitic capacitance between a first wiring formed on the bottom side of the active layer and a gate wiring can be reduced. In addition, impurities can be injected in a self-aligning manner using a gate electrode though it was not possible with a conventional bottom gate structure.
In accordance with one aspect of the present invention, the method for manufacturing a semiconductor device comprises the steps of:
forming a thin film device on a first substrate;
bonding a second substrate to the surface of the first substrate on which the thin film device is formed;
removing the first substrate, leaving the thin film device on the second substrate;
forming an opening portion for reaching the thin film device retained on the second substrate; and
cutting the second substrate so that the bonding portion of thin film device and the second substrate is removed, and removing the second substrate.
In accordance with another aspect of the present invention, the method for manufacturing a semiconductor device comprises the steps of:
forming a thin film device on a first substrate;
bonding a second substrate to the surface of the first substrate on which the thin film device is formed;
removing the first substrate, leaving the thin film device on the second substrate;
forming an opening portion for reaching the thin film device retained on the second substrate, and forming at lest one conductive layer contacting the thin film device through the opening portion; and
cutting the second substrate so that the bonding portion of the thin film device and the second substrate is removed, and removing the second substrate.
In accordance with another aspect of the present invention, the method for manufacturing a semiconductor device comprises the steps of:
forming a thin film device on a first substrate;
coating regions in which the thin film device is formed, and regions in which the thin film device is not formed, separately by using at least two types of adhesives, and bonding a second substrate to the surface of the first substrate on which the thin film device is formed;
removing the first substrate, leaving the thin film device on the second substrate;
forming an opening portion for reaching the thin film device retained on the second substrate; and
cutting the second substrate so that the regions coated with adhesive are removed.
In accordance with another aspect of the present invention, the method for manufacturing a semiconductor device comprises the steps of:
coating regions in which the thin film device is formed, and regions in which the thin film device is not formed, separately by using at least two types of adhesives, and bonding a second substrate to the thin film device formed on the first substrate;
removing the first substrate, leaving the thin film device on the second substrate;
forming an opening portion for reaching the thin film device retained on the second substrate, and forming at least one conductive layer contacting the thin film device through the opening portion; and
cutting the second substrate so that the regions coated with adhesive are removed.
In accordance with another aspect of the present invention, the method for manufacturing a semiconductor device comprises the steps of:
forming a first thin film device on one surface of a first substrate;
partially bonding a thin film or a second thin film device to a second substrate;
bonding the thin film or the second thin film device bonded to the second substrate to the first thin film device formed on the first substrate;
removing the first substrate, leaving the first thin film device on the second substrate;
forming an opening portion in the first thin film device retained on the second substrate; and
cutting the second substrate so that the bonding portion of the thin film, or the second thin film device, and the second substrate is removed, and removing only the second substrate, leaving the thin film or the second thin film device.
In accordance with another aspect of the present invention, the method for manufacturing a semiconductor device comprises the steps of:
forming a first thin film device on one surface of a first substrate;
partially bonding a thin film or a second thin film device to a second substrate;
bonding the thin film or the second thin film device bonded to the second substrate to the first thin film device formed on the first substrate;
removing the first substrate, leaving the thin film device on the second substrate;
forming at least one conductive layer on the first thin film device retained on the second substrate; and
cutting the second substrate so that the bonding portion of the thin film, or the second thin film device, and the second substrate is removed, and removing only the second substrate, leaving the thin film or the second thin film device.
In accordance with another aspect of the present invention, the method for manufacturing a semiconductor device comprises the steps of:
forming a first thin film device on one surface of a first substrate;
coating locations in which the thin film device exists, and locations in which the thin film device does not exist, separately by using at least two types of adhesives, and bonding a thin film or a second thin film device to a second substrate;
bonding the thin film or the second thin film device bonded to the second substrate to the first thin film device formed on the first substrate;
removing the first substrate, leaving the thin film device on the second substrate;
forming an opening portion in the first thin film device retained on the second substrate; and
cutting the second substrate so that a portion of the thin film, or the second thin film device, and the second substrate is removed, and removing only the second substrate, leaving the thin film or the second thin film device.
In accordance with another aspect of the present invention, the method for manufacturing a semiconductor device comprises the steps of:
forming a first thin film device on one surface of a first substrate;
coating locations in which the thin film device exists, and locations in which the thin film device does not exist, separately by using at least two types of adhesives, and bonding a thin film or a second thin film device to a second substrate;
bonding the thin film or the second thin film device bonded to the second substrate to the first thin film device formed on the first substrate;
removing the first substrate, leaving the first thin film device on the second substrate;
forming at least one conductive layer in the first thin film device retained on the second substrate; and
cutting the second substrate so that a portion of the thin film, or the second thin film device, and the second substrate is removed, and removing only the second substrate, leaving the thin film or the second thin film device.
In accordance with another aspect of the present invention, the method for manufacturing a semiconductor device comprises the steps of:
forming a first thin film device on one surface of a first substrate;
partially bonding a thin film or a second thin film device to a second substrate;
bonding the thin film or the second thin film device bonded to the second substrate to the first thin film device formed on the first substrate; and
cutting the second substrate so that the bonding portion of the thin film, or the second thin film device, and the second substrate is removed, and removing only the second substrate, leaving the thin film or the second thin film device.
In accordance with another aspect of the present invention, the method for manufacturing a semiconductor device comprises the steps of:
forming a first thin film device on one surface of a first substrate;
coating locations in which the thin film device exists, and locations in which the thin film device does not exist, separately by using at least two types of adhesives, and bonding a thin film or a second thin film device to a second substrate;
bonding the thin film or the second thin film device bonded to the second substrate to the first thin film device formed on the first substrate; and
cutting the second substrate so that a portion of the thin film, or the second thin film device, and the second substrate is removed, and removing only the second substrate, leaving the thin film or the second thin film device.
In accordance with another aspect of the present invention, the method for manufacturing a semiconductor device comprises the steps of:
forming a first thin film device on one surface of a first substrate;
partially bonding a thin film or a second thin film device to a second substrate;
introducing liquid crystals between the first thin film device formed on the first substrate and the thin film, or the second thin film device, bonded to the second substrate; and
cutting the first substrate, the first thin film device, the second substrate, and the thin film or the second thin film device, so that a portion of the first substrate, the first thin film device, the second substrate, and the thin film or the second thin film device is removed, and removing the second substrate, leaving the thin film or the second thin film device.
In accordance with another aspect of the present invention, the method for manufacturing a semiconductor device comprises the steps of:
forming a first thin film device on one surface of a first substrate;
coating locations in which the thin film device exists, and locations in which the thin film device does not exist, separately by using at least two types of adhesives, and bonding a thin film or a second thin film device to a second substrate;
introducing a liquid crystal between the first thin film device formed on the first substrate and the thin film, or the second thin film device, bonded to the second substrate; and
cutting the first substrate, the first thin film device, the second substrate, and the thin film or the second thin film device, so that a portion of the first substrate, the first thin film device, the second substrate, and the thin film or the second thin film device is removed, and removing the second substrate, leaving the thin film or the second thin film device.
In accordance with another aspect of the present invention, the method for manufacturing a semiconductor device comprises the steps of:
forming a thin film device on one face of a first substrate;
partially bonding a polarization film or a polarization plate to a second substrate;
bonding the polarization film or the polarization plate bonded to the second substrate to the thin film device formed on the first substrate;
removing the first substrate, leaving the thin film device on the second substrate;
forming an opening portion in the thin film device retained on the second substrate; and
cutting the second substrate so that the bonding portion of the polarization film, or the polarization plate, and the second substrate is removed, and removing only the second substrate, leaving the polarization film or the polarization plate.
In accordance with another aspect of the present invention, the method for manufacturing a semiconductor device comprises the steps of:
forming a thin film device on one face of a first substrate;
partially bonding a polarization film or a polarization plate to a second substrate;
bonding the polarization film or the polarization plate bonded to the second substrate to the thin film device formed on the first substrate;
removing the first substrate, leaving the thin film device on the second substrate;
forming at least one conductive layer on the thin film device retained on the second substrate; and
cutting the second substrate so that the bonding portion of the polarization film, or the polarization plate, and the second substrate is removed, and removing only the second substrate, leaving the polarization film or the polarization plate.
In accordance with another aspect of the present invention, the method for manufacturing a semiconductor device comprises the steps of:
forming a thin film device on one face of a first substrate;
coating locations in which the thin film device exists, and locations in which the thin film device does not exist, separately by using at least two types of adhesives, and bonding a polarization film or a polarization plate to a second substrate;
bonding the polarization film or the polarization plate bonded to the second substrate to the thin film device formed on the first substrate;
removing the first substrate, leaving the thin film device on the second substrate;
forming an opening portion in the thin film device retained on the second substrate; and
cutting the second substrate so that a portion of the polarization film, or the polarization plate, and the second substrate is removed, and removing only the second substrate, leaving the polarization film or the polarization plate.
In accordance with another aspect of the present invention, the method for manufacturing a semiconductor device comprises the steps of:
forming a thin film device on one face of a first substrate;
coating locations in which the thin film device exists, and locations in which the thin film device does not exist, separately by using at least two types of adhesives, and bonding a polarization film or a polarization plate to a second substrate;
bonding the polarization film or the polarization plate bonded to the second substrate to the thin film device formed on the first substrate;
removing the first substrate, leaving the thin film device on the second substrate;
forming at least one conductive layer on the thin film device retained on the second substrate; and
cutting the second substrate so that a portion of the polarization film, or the polarization plate, and the second substrate is removed, and removing only the second substrate, leaving the polarization film or the polarization plate.
In accordance with another aspect of the present invention, the method for manufacturing a semiconductor device comprises the steps of:
forming a thin film device on one surface of a first substrate;
forming an electrode on the thin film device;
partially bonding a second substrate to the thin film device formed on the first substrate, and;
removing the first substrate, leaving the thin film device on the second substrate;
forming an opening portion in the thin film device retained on the second substrate;
cutting the second substrate so that the bonding portion of the thin film device and the second substrate is removed, and removing the second substrate; and
forming and overlapping a plurality of thin film devices from the thin film device obtained in accordance with the preceding steps, and making the electrodes formed on the top and an electrode formed on the bottom of the thin film devices conductive.
In accordance with another aspect of the present invention, the method for manufacturing a semiconductor device comprises the steps of:
forming a thin film device on one surface of a first substrate;
forming an electrode on the thin film device;
partially bonding a second substrate to the thin film device formed on the first substrate;
removing the first substrate, leaving the thin film device on the second substrate;
forming an opening portion in the thin film device retained on the second substrate, and forming at least one conductive layer to form an electrode;
cutting the second substrate so that the bonding portion of the thin film device and the second substrate is removed, and removing the second substrate; and
forming and overlapping a plurality of thin film devices from the thin film device obtained in accordance with the preceding steps, and making the electrodes formed on the top and bottom of the thin film devices conductive.
In accordance with another aspect of the present invention, the method for manufacturing a semiconductor device comprises the steps of:
forming a thin film device on one surface of a first substrate;
forming an electrode on the thin film device;
coating locations in which the thin film device exists, and locations in which the thin film device does not exist, separately by using at least two types of adhesives, and bonding a second substrate to the thin film device formed on the first substrate;
removing the first substrate, leaving the thin film device on the second substrate;
forming an opening portion in the thin film device retained on the second substrate;
cutting the second substrate so that a portion of the thin film device and the second substrate is removed, and removing the second substrate; and
forming and overlapping a plurality of thin film devices from the thin film device obtained in accordance with the preceding steps, and making the electrodes formed on the top and an electrode formed on the bottom of the thin film devices conductive.
In accordance with another aspect of the present invention, the method for manufacturing a semiconductor device comprises the steps of:
forming a thin film device on one surface of a first substrate;
forming an electrode on the thin film device;
coating locations in which the thin film device exists, and locations in which the thin film device does not exist, separately by using at least two types of adhesives, and bonding a second substrate to the thin film device formed on the first substrate;
removing the first substrate, leaving the thin film device on the second substrate;
forming an opening portion in the thin film device retained on the second substrate, and forming at least one conductive layer, forming an electrode;
cutting the second substrate so that the bonding portion of the thin film device and the second substrate is removed, and removing the second substrate; and
forming and overlapping a plurality of thin film devices from the thin film device obtained in accordance with the preceding steps, and making the electrodes formed on the top and bottom of the thin film devices conductive.
In accordance with another aspect of the present invention, the method for manufacturing a semiconductor device comprises the steps of:
forming a first thin film device on one surface of a first substrate;
forming an electrode on the first thin film device;
partially bonding a thin film or a second thin film device having an opening portion to a second substrate; or forming an opening portion in the thin film or the second thin film device after partially bonding the thin film or the second thin film device to the second substrate;
bonding the thin film or the second thin film device bonded to the second substrate to the first thin film device formed on the first substrate;
removing the first substrate, leaving the first thin film device on the second substrate;
forming an opening portion in the first thin film device retained on the second substrate;
cutting the second substrate so that the bonding portion of the thin film, or the second thin film device, and the second substrate is removed, and removing only the second substrate, leaving the thin film or the second thin film device; and
forming and overlapping a plurality of thin film devices from the thin film device obtained in accordance with the preceding steps, and making the electrodes formed on the top and bottom of the thin film devices conductive.
In accordance with another aspect of the present invention, the method for manufacturing a semiconductor device comprises the steps of:
forming a first thin film device on one surface of a first substrate;
forming an electrode on the first thin film device;
partially bonding a thin film, or a second thin film device, having an opening portion, to a second substrate; or forming an opening portion in the thin film or the second thin film device after partially bonding the thin film or the second thin film device to the second substrate;
bonding the thin film or the second thin film device bonded to the second substrate to the first thin film device formed on the first substrate;
removing the first substrate, leaving the first thin film device on the second substrate;
forming an opening portion in the first thin film device retained on the second substrate, and forming at least one conductive layer to form an electrode;
cutting the second substrate so that the bonding portion of the thin film, or the second thin film device, and the second substrate is removed, and removing only the second substrate, leaving the thin film or the second thin film device; and
forming and overlapping a plurality of thin film devices from the thin film device obtained in accordance with the preceding steps, and making the electrodes formed on the top and bottom of the thin film devices conductive.
In accordance with another aspect of the present invention, the method for manufacturing a semiconductor device comprises the steps of:
forming a first thin film device on one surface of a first substrate;
forming an electrode on the first thin film device;
coating locations in which the thin film device exists, and locations in which the thin film device does not exist, separately by using at least two types of adhesives, and bonding a thin film, or a second thin film device, having an opening portion, to a second substrate; or coating locations in which the thin film device exists, and locations in which the thin film device does not exist, separately by using at least two types of adhesives to form an opening portion in the thin film or the second thin film device after bonding the thin film or the second thin film device to the second substrate;
bonding the thin film or the second thin film device bonded to the second substrate to the first thin film device formed on the first substrate;
removing the first substrate, leaving the first thin film device on the second substrate;
forming an opening portion in the first thin film device retained on the second substrate;
cutting the second substrate so that a portion of the thin film, or the second thin film device, and the second substrate is removed, and removing only the second substrate, leaving the thin film or the second thin film device; and
forming and overlapping a plurality of thin film devices from the thin film device obtained in accordance with the preceding steps, and making the electrodes formed on the top and bottom of the thin film devices conductive.
In accordance with another aspect of the present invention, the method for manufacturing a semiconductor device comprises the steps of:
forming a first thin film device on one surface of a first substrate;
forming an electrode on the first thin film device;
coating locations in which the thin film device exists, and locations in which the thin film device does not exist, separately by using at least two types of adhesives, and bonding a thin film, or a second thin film device, having an opening portion, to a second substrate; or coating locations in which the thin film device exists, and locations in which the thin film device does not exist, separately by using at least two types of adhesives to form an opening portion in the thin film or the second thin film device after bonding the thin film or the second thin film device to the second substrate;
bonding the thin film or the second thin film device bonded to the second substrate to the first thin film device formed on the first substrate;
removing the first substrate, leaving the first thin film device on the second substrate;
forming an opening portion in the first thin film device retained on the second substrate, and forming at least one conductive layer to form an electrode;
cutting the second substrate so that a portion of the thin film, or the second thin film device, and the second substrate is removed, and removing only the second substrate, leaving the thin film or the second thin film device; and
forming and overlapping a plurality of thin film devices from the thin film device obtained in accordance with the preceding steps, and making the electrodes formed on the top and bottom of the thin film devices conductive.
In accordance with another aspect of the present invention, the method for manufacturing a semiconductor device comprises the steps of:
forming a thin film device on a first substrate;
bonding the surface of the first substrate on which the thin film device is formed to a second substrate;
removing the first substrate; and
forming an opening portion in the thin film device retained on the second substrate.
In accordance with another aspect of the present invention, the method for manufacturing a semiconductor device comprises the steps of:
forming a thin film device on a first substrate;
bonding the surface of the first substrate on which the thin film device is formed to a second substrate;
removing the first substrate; and
forming at least one conductive layer in the thin film device retained on the second substrate.
In accordance with another aspect of the present invention, the semiconductor device comprises a semiconductor formed on an insulator as an active layer, wherein: at least one conductive layer is formed above, and below, the active layer using a material capable of withstanding a temperature of 550xc2x0 C.
In accordance with another aspect of the present invention, the thin film transistor comprises a semiconductor formed on an insulator as an active layer, comprising:
a gate insulating film on the active layer;
a gate electrode on the gate insulating film;
performing impurity addition, using the gate electrode as a mask; and
a wiring on the side opposite the gate electrode, with respect to the active layer, using a material having a resistance to heat equal to or less than 550xc2x0 C.
In accordance with another aspect of the present invention, the semiconductor device comprises a semiconductor formed on an insulator as an active layer, comprising:
a pair of polarization films;
a pixel electrode;
a thin film transistor composed of: an active layer; a gate insulating film contacting the active layer; and a gate electrode contacting the gate insulating film;
a wiring connected to the active layer from the gate electrode side;
an opposing electrode;
liquid crystals between a pixel electrode formed between the pair of polarization films, and the opposing electrode;
a sealant; and
an orientation film.
In accordance with another aspect of the present invention, the semiconductor device comprises a semiconductor formed on an insulator as an active layer, comprising:
a pair of polarization films;
a thin film transistor composed of: an active layer contacting a first insulating film; a gate insulating film contacting the active layer; and a gate electrode contacting the gate insulating film;
a third insulating film contacting the gate electrode;
a passivation film contacting the third insulating film;
a wiring electrically connected to each thin film transistor through an opening portion formed in the third insulating film and in the gate insulating film;
a pixel electrode formed in the surface opposite that in which the gate electrode of the active layer is formed;
an orientation film formed contacting the pixel electrode;
an opposing electrode formed in one polarization film of the pair of polarizing films;
liquid crystals between the pixel electrode, formed between the pair of polarizing films, and the opposing electrode; and
a sealant formed between the first insulating film and the pair of polarizing films.